RewriteEngine On

RewriteRule ^go/([p0-9]*)/([a-zA-Z0-9]+)/?$ /go.php?pid=$1&tid=$2 [QSA,L]
RewriteRule ^go/([p0-9]*)/?$ /go.php?pid=$1 [QSA,L]

RewriteRule ^imp/([p0-9]*)/([a-zA-Z0-9]+)/?$ /imp.php?pid=$1&tid=$2 [QSA,L]
RewriteRule ^imp/([p0-9]*)/?$ /imp.php?pid=$1 [QSA,L]

RewriteRule ^events/([A-Za-z]+)/?$ /eventapi/api.php?action=$1 [QSA,L]

RewriteRule ^[A-Za-z0-9]+/(p[0-9]+)/([a-zA-Z0-9]+)/?$ /index.php?pid=$1&tid=$2 [QSA,L]
RewriteRule ^[A-Za-z0-9]+/(p[0-9]+)/?$ /index.php?pid=$1 [QSA,L]

RewriteRule ^(p[0-9]*)/([a-zA-Z0-9]+)/?$ /index.php?pid=$1&tid=$2 [QSA]
RewriteRule ^(p[0-9]*)/?$ /index.php?pid=$1 [QSA]